The present invention relates generally to sign frames and poster display devices for use in displaying large signs and displays. More particularly, the invention relates to display frames for securely holding in place large signs (on the order of 3-5 feet or larger on each side) and which provide means for accommodating stretching (expansion and/or contraction) of the sign or poster in the frame.
There are numerous sign frames and poster display devices known today which are used for displaying various signs and messages for advertisement and information to the public. The present invention has as its primary purpose the design of a sign frame and poster display device which can be used for displaying large signs which are several feet in length along each edge and in which the signs and displays are typically exposed to temperature and/or weather conditions which will alter the shape of the signs and displays. Large signs made of plastic or similar material, can expand or contract a considerable amount (e.g., a half-inch or more for every ten feet in length) and this can adversely affect the aesthetics and readability of a large sign or display as well as the integrity of the sign panel itself. This is particularly true where the signs are displayed outdoors and subjected to extremes in temperatures, where the signs are highlighted or backlighted and subjected to changes in temperatures, or where the signs are placed on moving vehicles and are also exposed to significant wind forces.
One of the primary purposes of the present invention is to provide a sign and poster display frame for use on the sides of truck trailers. Truck trailers typically have sides which have a surface area on the order of 6-8 feet in heighth and 15-45 feet in length. The sides of truck trailers are not used to a significant extent today for advertising purposes; instead most trailers carry either the name of a trucking company or the business entity which owns the trailer. Some similar trucks used in metropolitan areas to deliver beverages, and some busses and taxicabs, often have posters or signs mounted on them, but these are usually of a small size and are not exposed to the weather and wind conditions encountered with highway truck trailers.
It would be possible to permanently paint advertising messages on truck trailers in a manner similar to billboards, but this would be expensive and also would be difficult to change quickly on a regular basis. Also, painted surfaces have a tendency to chip or peel and the paint might not adhere effectively or efficiently to the metal sides of truck trailers. In addition, many truck trailers have posts or other structures on their sides which would create a nonuniform and uneven appearance for an advertisement.
If large canvas or plastic sheets of material were fastened on the sides of the truck trailers or other large surfaces, they would be exposed to the wind and thermal forces which would cause them to wrinkle and buckle making the message both unsightly and difficult to read. To prevent this, the posters and sign displays would have to be secured tightly initially which would only increase the problems when the signs and posters were exposed to wind and thermal expansion and contraction problems. In addition, in cold weather conditions, the thermal contraction of large pieces of plastic if held tightly on the perimeter might result in a cracking or tearing of the sign which would ruin it. If a crack or tear developed in the sign and it was exposed to high speed wind conditions, the resultant effect on the sign would be disasterous. Not only would the sign not present the intended message to the public, but the hanging and flapping portions could create safety problems.
Another primary purpose of the invention is to provide a display frame for use with lighted sign devices. In large lighted advertising displays today, especially those in which the sign panels are backlighted, special care has to be taken to prevent warping, buckling or distortion of the sign panels. Lights produce a significant amount of heat energy which expands the sign panels and adversely affects the aesthetics and readability of the message on the sign. In large backlighted displays, the sign panel is typically sandwiched between two panels of glass or plexiglass (acrylic) in order to prevent such distortion. These displays are heavy and expensive, however, and also make changing of the sign panels time consuming and difficult. Plexiglass further gets dirty and marred quickly and thus needs to be replaced frequently.
It is the main object of the present invention to provide a sign frame and poster display device which overcomes all the aforementioned problems. It is another object of the present invention to provide a display frame which will securely hold and accommodate large sign and poster displays on the order of several feet along each edge. It is still a further object of the present invention to provide a sign frame and poster display device which can compensate for the thermal expansion and contraction forces on large sign displays and also hold the sign and poster so that it can accommodate large wind forces if it is attached to a moving vehicle.
It is still another object of the invention to provide a sign frame and poster display device for large signs and posters which allows the sign or poster to be quickly and easily changed when desired. Another object of the invention is to allow use of a large disposable sign which is economical to produce and can be changed frequently.
In accordance with the present invention, a sign frame and poster display device is provided which has means for holding the sign or poster securely on all of its edges and yet at the same time allows for expansion and contraction of the sign due to wind and thermal forces. The sign frames and poster display devices can be of any length and width and comprise a plurality of elongated sections positioned on the side of the truck trailer or other planar surface as desired. Each of the frame sections has a base member and a hinged cover member which are pivoted together along their outside edges. A slide member is resiliently mounted inside the base member and is adapted for movement in any direction in a plane parallel to the sign and poster surface. A plurality of the resiliently mounted slide members are provided in each of the elongated frame sections. Each of the slide members has a post or peg which is adapted to mate with corresponding apertures near the perimeter of the poster or sign display.
The cover member is adapted to be pivoted into an open position in order to allow mounting of a new sign or changing of an old sign. The cover member is also adapted to be rotated into a closed position over the edge of the sign thereby hiding the slide member and also securing the sign from unwanted removal from the frame.
Each of the frame sections also has a plurality of leaf springs or similar resilient biasing members which bias the cover into its open and closed positions. The positioning of the pivot between the cover member and the base member in cooperation with the spring biasing member creates an over-center force which securely holds the cover member in its open and closed positions.
Further objects, features and advantages of the present invention will become apparent from a review of the drawings when read in accordance with the accompanying specification.